JP4928885B2 - Air conditioner for vehicles - Google Patents

Description

  The present invention relates to a vehicle air conditioner that determines an abnormality of a blower motor.

  Conventionally, an applied voltage value and an energized current value to a blower motor constituting a vehicle air conditioner are detected, and the detected energized current value exceeds a reference current value set in advance corresponding to the applied voltage value. In this case, a vehicle air conditioner including a lock determination unit that determines that the blower motor is locked has been proposed (see Patent Document 1).

  In this vehicle air conditioner, when the vehicle air conditioner is operating with inside air circulation or outside air introduction or when the vehicle air conditioner is operating with outside air introduction, the reference current value increases as the vehicle speed increases. Thus, it is disclosed that erroneous determination is avoided. Further, it is disclosed that when the atmospheric temperature is lowered, and further, when the ventilation resistance is increased by switching the blowout port, erroneous determination is avoided by setting the reference current value to be larger.

Japanese Patent No. 3304362 (FIG. 2)

  However, in the vehicle air conditioner according to the above prior art, in order to prevent the blower motor from burning or the energization element from being destroyed, the energization current value exceeds the reference current value (set maximum current value). It only detects the blower motor lock, and it can detect an abnormality in a blower motor other than the lock, for example, an abnormality when the energization current value falls below the reference current value due to deterioration of the brush in the blower motor, etc. Can not.

  The present invention has been made in consideration of such a problem, and provides an air conditioner for a vehicle that can detect an abnormality even when an energization current value of a blower motor falls below a reference current value. The purpose is to provide.

  Another object of the present invention is to provide a vehicle air conditioner that can appropriately detect an abnormality of a blower motor in response to a change in energization current value of the blower motor.

  An air conditioner for a vehicle according to the present invention detects an applied voltage value and an energized current value of a blower motor, compares the energized current value with a reference current value corresponding to the applied voltage value, and detects an abnormality of the blower motor. A vehicle air conditioner including an abnormality determining means for determining includes the following features (1) to (3).

  (1) Lifetime operating time measuring means for measuring the lifetime operating time of the blower motor, and reference current value correcting means for correcting the reference current value according to the measured lifetime operating time, the abnormality determining means Is characterized in that an abnormality of the blower motor is determined by comparing the reference current value corrected according to the lifetime operation time and the energization current value.

  Here, the lifetime operating time of the blower motor is the cumulative operating time of the blower motor.

  According to the present invention, the reference current value correcting unit corrects the reference current value according to the applied voltage value according to the lifetime operating time of the blower motor measured by the lifetime operating time measuring unit, and the abnormality determining unit corrects the lifetime operation. Since the blower motor abnormality is judged by comparing the reference current value corrected with time and the energization current value, it is possible to appropriately detect the abnormality of the blower motor corresponding to the secular change of the energization current value of the blower motor. it can.

  (2) In the above feature (1), the reference current value has a reference current value width between a maximum reference current value and a minimum reference current value, and the reference current value width is a lifetime operating time of the blower motor. In the initial stage (low cumulative operating time) and the end of lifetime operating time (high cumulative operating time), it is set wider than the stable period of the lifetime operating time (medium cumulative operating time) The abnormality determining means determines that the blower motor is abnormal when the energized current value is not less than the maximum reference current value or not more than the minimum reference current value.

  According to the present invention, the abnormality determining means determines that the blower motor is abnormal when it is greater than or equal to the maximum reference current value set according to the applied voltage or less than the minimum reference current value, and the maximum reference current value and the The reference current value width formed by the minimum reference current value is set wider than the stable period of the lifetime operating time at the beginning of the lifetime operating time of the blower motor and at the end of the lifetime operating time. Abnormalities in the blower motor can be appropriately detected in response to changes over time in the energization current value. Further, since the lock is not simply detected, it is also possible to detect an abnormality when the energization current value of the blower motor becomes a value lower than the reference current value.

  It should be noted that the inventors of this application show that when the blower motor is a DC brush motor, the surface roughness of the commutator and the brush is relatively large at the initial stage of the lifetime, and the spring property of the brush is also high. Because of the high voltage, there is a high possibility that the contact of the brush with the commutator will be non-uniform, and even with the same applied voltage value, the energizing current value will be smaller than the energizing current value in the stable period, and it will operate for a lifetime. At the end of time, there is a high possibility that the contact of the brush with the commutator is weak and non-uniform due to wear of the commutator and brush and deterioration of the spring property, etc., and the current value is stable even at the same applied voltage value. It has been found that it is smaller than the current value of the current period.

  (3) In the above feature (2), when the initial side and the end side of the reference current value width are set wide, the maximum reference current value is fixed and the minimum reference current value is lowered. Features.

  According to this invention, since the minimum reference current value is set to a smaller value in the initial period of the lifetime operating time of the blower motor and the end of the lifetime operating time, compared to the stable period of the lifetime operating time, Abnormalities in the blower motor can be appropriately detected in response to changes over time in the energization current value of the blower motor.

  According to the present invention, it is possible to appropriately detect an abnormality of the blower motor in accordance with the secular change of the energization current value of the blower motor.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a main configuration of a vehicle air conditioner 10 according to an embodiment of the present invention.

  A vehicle air conditioner 10 mounted on a vehicle basically includes a blower motor 12 having a blower fan fixed to a shaft, a microcomputer 14 that controls the rotation of the blower motor 12 and determines an abnormality of the blower motor 12. Consists of

  The microcomputer 14 includes an air conditioning panel 16, various sensors (vehicle interior temperature sensor, vehicle exterior temperature sensor, solar radiation sensor, etc.) 18, A / D converters 21 to 23, a D / A converter 24, and a relay 26, a fixed terminal of the ignition switch 28 to which the battery voltage Vb is supplied, and a warning unit 30 such as a display or an alarm device are connected.

  A common terminal of the ignition switch 28 is connected to an in-vehicle battery 32. When the ignition switch 28 is turned on, the microcomputer 14 constituting the vehicle air conditioner 10 is operated by the operation of the air conditioning panel 16 to perform the air conditioning operation.

  As is well known, the air conditioning panel 16 includes an air conditioner switch 52 that is an air conditioner on / off switch and a fan switch 54 that is a fan on / off switch, as well as a mode switch that switches an air outlet, and rotation of the blower motor 12. A fan speed switch for changing the speed, a temperature adjustment switch for setting the temperature in the passenger compartment, an inside / outside air changeover switch, a changeover switch between an auto air conditioner and a manual air conditioner, a liquid crystal display unit for displaying the state of these switches, and the like. When the air conditioning switch 52 is switched to the on state, the fan switch 54 is also automatically switched to the on state. That is, the blower motor 12 rotates when either one or both of the air conditioning switch 52 and the fan switch 54 are in the on state. The microcomputer 14 can detect the time during which the blower motor 12 is rotating as the operation time of the blower motor 12.

  The blower motor 12 is a DC brush motor in which current is supplied from a brush to a motor coil through a commutator. One end of the blower motor 12 is connected to a battery 32 that supplies a battery voltage Vb through a relay 26, and the other end is connected to a transistor 34 and a resistor. It is grounded through the device 36.

  The applied voltage value Vm to the blower motor 12 is detected by the microcomputer 14 through the A / D converters 21 and 22, and the energization current value Im of the blower motor 12 is detected by the microcomputer 14 through the A / D converter 23.

  The transistor 34 for driving the blower motor 12 is driven and controlled from the microcomputer 14 through the D / A converter 24.

  The microcomputer 14 includes a ROM (read only memory) in which programs and the like are stored, and a CPU (central processing unit) that functions as means for realizing control, calculation, and judgment by executing the programs stored in the ROM. And a random access memory (RAM), an EEPROM 42 which is a storage device which can be electrically rewritten as a nonvolatile memory, a timer 40, a clock, and the like.

  FIG. 2 shows a functional block diagram of the microcomputer 14. As can be seen from FIG. 2, the microcomputer 14 basically includes a lifetime operating time measuring means 102, a reference current value correcting means 104, an applied voltage value detecting means 106, an energized current value detecting means 108, and an abnormality determining means 110. Function as.

  The EEPROM 42 includes a lifetime operating time storage unit 42a and a reference current value storage unit 42b. The lifetime operating time storage unit 42a stores a lifetime operating time TL that is a cumulative value (integrated value) of the blower motor operating time that is the time during which the blower motor 12 is rotating. Therefore, the lifetime operation time TL is updated by the time that the blower motor 12 is rotating (operating). In this embodiment, as described above, whether or not the blower motor 12 is rotating is determined by either the air conditioning switch 52 or the fan switch 54 or a period in which the blower motor 12 is turned on at the same time. However, the rotation time of the blower motor 12 may be detected, or the rotation time of the blower fan fixed to the blower motor 12 and rotating.

  In this embodiment, three reference current value maps are stored in the reference current value storage unit 42b. In order to facilitate understanding of the three reference current value maps, the relationship between the motor current of the blower motor 12 that is a DC brush motor and the lifetime TL will be described.

  FIG. 3 is a characteristic diagram showing a relationship 120 of the motor current of the blower motor 12 with respect to the lifetime operation time TL when the applied voltage value Vm is a predetermined constant value. From FIG. 3, in the initial period of the lifetime operation time TL from the operation start time t0 to the time t1, the motor current gradually increases due to the gradual elimination of instability per brush with respect to the commutator. In addition, a motor current having a predetermined constant value flows during the stable period of the lifetime operation time TL from the initial elapsed time t1 to the start time t2 of the life deterioration period (end stage). Furthermore, in the last period from the start time t2 of the life deterioration period to the life time t3, the motor current gradually decreases again due to wear deterioration of the brush and commutator.

  As a specific time, for example, the initial period (t0 to t1) of the lifetime operating time TL is about 500 to 600 hours, and if the blower motor 12 is rotating for 2 hours a day, it is within one year. After that, the brush current becomes stable, and thereafter, after a stable period of about 4000 hours (t1 to t2: about 5 to 6 years in the same way), the motor current gradually decreases about 500 to 600. It is the end of time (t2-t3). Note that the specific time of the lifetime operation time TL with respect to the relationship 120 in FIG. 3 differs depending on the model of the blower motor 12.

  Accordingly, the three reference current value maps stored in the reference current value storage unit 42b will be described.

  4A is a reference current value map 121 that is referred to in the initial period (t0 to t1) of the lifetime operation time TL, and FIG. 4B is a reference current value map 122 that is referred to in the stable period (t1 to t2) of the lifetime operation time TL. FIG. 4C is a reference current value map 123 referred to at the end of the lifetime operation time TL (t2 to t3).

  In the reference current value maps 121, 122, 123, there are a blower motor upper limit side abnormal area AA0, a lower limit side abnormal area AA1, AA2, AA3, and normal areas NA1, NA2, NA3 surrounded by these.

  The blower motor upper limit abnormality region AA0 is an equal region (region having the same shape) in the reference current value maps 121 to 123, and the change in the maximum reference current value Imax with respect to the change in the applied voltage value Vm has the same characteristics. . On the other hand, the lower limit side abnormal areas AA1, AA2, and AA3 are different areas, and changes in the minimum reference current values Imin1, Imin2, and Imin3 with respect to changes in the applied voltage value Vm have different characteristics. That is, when the applied voltage value Vm is the same applied voltage value, for example, the applied voltage value Vm = Va, the maximum reference current value Imax of the reference current value maps 121 to 123 is the same value Imax (Va), but the minimum reference voltage value The magnitude relationship among Imin1, Imin2, and Imin3 is Imin2 (Va)> Imin1 (Va)> Imin3 (Va). That is, the reference current value width ΔI (ΔI1, ΔI2, ΔI3) between the maximum reference current value Imax and the minimum reference voltage value Imin (Imin1, Imin2, Imin3) is a reference for the stable period of the lifetime operation time TL of the blower motor 12. Compared with the current value width ΔI2, the initial reference current value width ΔI1 of the lifetime operating time TL and the reference current value width ΔI3 of the end of the lifetime operating time TL are set wider.

  Specifically, in the blower motor 12 of this embodiment, ΔI1≈5 [A] and ΔI3≈8 [A] are set with respect to ΔI2≈1 [A]. As a result of the setting as described above, the abnormality of the blower motor 12 can be determined with the highest accuracy in the stable period (t1 to t2), which is the longest lifetime operating time TL.

  In FIG. 2, the applied voltage value detecting means 106 detects the applied voltage value Vm as a voltage difference between the A / D converters 21 and 22 connected to both ends of the blower motor 12 of FIG. 1, and the detected applied voltage value Vm is detected. This is supplied to the reference current value correction means 104 and the abnormality determination means 110.

  The energization current value detection means 108 detects the energization current value Im as a value obtained by dividing the voltage drop value of the resistor 36 obtained by the A / D converter 23 by the resistance value of the resistor 36, and supplies it to the abnormality determination means 110. To do.

  The lifetime operating time measuring means (lifetime operating time measuring means) 102 is a timer 40 which is a time measuring means for a time during which the fan switch 54 is in an ON state (including a time during which the air conditioning switch 52 is in an ON state). The lifetime operating time TL stored in the lifetime operating time storage unit 42a is updated (accumulated). This update is performed, for example, when the ignition switch 28 is on. The lifetime operating time measuring unit 102 supplies the updated lifetime operating time TL read from the lifetime operating time storage unit 42 a to the reference current value correcting unit 104.

  The reference current value correcting unit 104 refers to the reference current value maps 121 to 123 corresponding to the supplied lifetime operating time TL, and applies the applied voltage value Vm (for example, Va) supplied by the applied voltage value detecting unit 106. The corresponding maximum reference current value Imax (Va) and minimum reference current value Imin (Va) are read and supplied to the abnormality determination means 110. The reference current value map 121 is referred to during the initial period (t0 to t1) of the lifetime reference time TL, the reference current value map 122 is referred to during the stable period (t1 to t2), and the final period (t2 to t3). In this period, the reference current value map 123 is referred to.

  The abnormality determination unit 110 calculates the energization current value Im supplied from the energization current value detection unit 108 and the maximum and minimum reference current values Imax and Imin corresponding to the applied voltage value Vm supplied from the reference current value correction unit 104. In comparison, if the energization current value Im is a value within the range of the maximum and minimum reference current values Imax and Imin (within the reference current value width ΔI), it is normal (Imax> Im> Imin), and the energization current value Im is the maximum reference current value Imax. When the value is equal to or greater than or equal to or smaller than the minimum reference current value Imin, it is determined as abnormal (Im ≧ Imax or Im ≦ Imin) and the determination result is supplied to the warning unit 30.

  A more detailed operation of the first embodiment of the vehicle air conditioner 10 constructed and operated as described above will be basically described with reference to the flowchart of FIG.

  When the ignition switch 28 is turned on, the microcomputer 14 wakes up. First, in step S1, the lifetime operating time measuring means 102 determines whether or not the fan switch 54 constituting the air conditioning panel 16 is turned on. The If it is determined to be in the on state, the process proceeds to step S2. Note that when the air conditioning switch 52 is in the on state, the fan switch 54 is also automatically in the on state, and in this case, the process proceeds to step S2.

  In step S <b> 2, the lifetime operating time measuring unit 102 reads the lifetime operating time TL of the blower motor 12 from the lifetime operating time storage unit 42 a of the EEPROM 42.

  In step S3, the lifetime operating time measuring unit 102 adds a new operating time to the read lifetime operating time TL, and in step S4, adds the new lifetime operating time TL to the lifetime operating time storage unit 42a. Save and update lifetime working time TL.

  In steps S5 to S7, the reference current value correcting unit 104 determines whether the updated lifetime operation time TL is in the initial period (time t0 to time t1) in the lifetime operation period TL shown in FIG. 3 (S5: YES) Whether it is in the stable period (time t1 to t2) (S5: NO → S6: YES), whether it is in the end period (time t2 to t3) (S5, S6: NO → S7: YES), or the end stage (life time t3) It is determined whether it has passed (S5 to S7: NO).

  If the reference current value correcting unit 104 determines that the initial value is based on these determination results, the reference current value correction unit 104 selects the reference current value map 121 shown in FIG. 4A in the reference current value storage unit 42b in step S8. If the stable period is determined, the reference current value map 122 shown in FIG. 4B is selected in step S9. If the final period is determined, the reference current value map 123 shown in FIG. 4C is determined in step S10. Select. If it is determined that the end stage has passed, in step S11, the warning unit 30 is informed that the life of the blower motor 12 has passed, and the process returns to step S1. In this case, the warning unit 30 gives a warning to the user of the vehicle air conditioner 10 by displaying on the display unit that the blower motor 12 needs to be replaced.

  When any one of the reference current value maps 121 to 123 is selected, the voltage drop of the blower motor 12 is detected as the applied voltage value Vm by the applied voltage value detecting means 106 through the A / D converters 21 and 22 in step S12. The reference current value correction unit 104 and the abnormality determination unit 110 are supplied.

  Next, in step S13, the reference current value correcting unit 104 refers to the selected reference current value maps 121 to 123, and calculates the maximum reference current value Imax and the minimum reference current value Imin from the detected applied voltage value Vm. To the abnormality determination means 110.

  Next, in step S14, the voltage drop of the resistor 36 is detected through the A / D converter 23, and this voltage drop is stored in advance in the resistance value of the resistor 36 (not shown in ROM) by the energizing current value detecting means 108. .) Is detected and supplied to the abnormality determination means 110.

  The abnormality determination unit 110 determines the magnitude of the energization current value Im detected in steps S15 and S16 and the maximum and minimum reference current values Imax and Imin calculated with reference to the reference current value maps 121 to 123 in step S13. In comparison, when the energized current value Im is less than the maximum reference current value Imax (step S15: YES) and exceeds the minimum reference current value Imin (step S16: YES), the current value Im is a value within the reference current value width ΔI (Imax). > Im> Imin), it is determined that the blower motor 12 is normal, and the process returns to step S1, which is a value not less than the maximum reference current value Imax (step S15: NO) or not more than the minimum reference current value Imin (step S16: NO). In this case (Im ≧ Imax or Im ≦ Imin), the warning unit 30 is blocked in step S11. Returns to step S1 inform that an abnormality in Amota 12 has occurred. In this case, the warning unit 30 displays on the display unit or the like that an abnormality has occurred in the blower motor 12 (or that the blower motor 12 needs to be replaced instead) and gives a warning to the user. .

  As described above, in the first embodiment, the reference current value correcting unit 104 applies the initial, stable period, or end period application in accordance with the lifetime operating time TL of the blower motor 12 measured by the lifetime operating time measuring unit 102. The reference current value maps 121 to 123 having the reference current value width ΔI in which the reference current value is corrected according to the voltage value Vm are selected, the corrected maximum and minimum reference current values ΔImax and ΔImin are calculated, and the energization current value Im Therefore, the abnormality of the blower motor 12 can be appropriately detected in accordance with the secular change of the energization current value Im of the blower motor 12.

  In this case, the energization current value Im takes into account the non-uniformity of contact with the commutator of the brush at the initial stage of the lifetime TL of the blower motor 12, and wear of the brush and the commutator at the end of the lifetime TL. In consideration of non-uniformity, etc., considering that the variation is larger than the stable period of the lifetime TL, the reference current value width ΔI is set to the initial lifetime lifetime TL of the blower motor 12 and the lifetime lifetime TL. At the end of the period, since it is set wider than the stable period of the lifetime operating time TL, it is possible to appropriately detect the abnormality of the blower motor 12 corresponding to the secular change of the conduction current value Im of the blower motor 12. it can. When the reference current value width ΔI is set wide, the maximum reference current value Imax is fixed, and the minimum reference current value Imin is changed, so that the initial and final periods are smaller than the energization current value Im in the stable period. It is possible to make corrections that match the actual situation.

  As described above, by correcting the reference current value width ΔI corresponding to the minimum and maximum reference current values Imax and Imin widely in the initial stage and the end stage, the occurrence of misjudgment in the initial stage and the end stage of the lifetime TL can be reduced, and the stable period By making a narrow correction, a highly accurate abnormality determination can be performed in the stable period of the lifetime TL.

  Next, a second embodiment will be described.

  In the second embodiment, in the reference current value storage unit 42b, in the reference current value maps 121 to 123 shown in FIGS. 4A to 4C, during the stable period (t1 to t2) of the lifetime operation time TL shown again in FIG. 6A. A reference current value map 122 to be referred to is stored, and a map (correction coefficient map or correction coefficient characteristic) 124 of the correction coefficient K with respect to the lifetime TL shown in FIG. 6B is stored. The correction coefficient K is set to K = 1 in the stable period, and is set to be gradually smaller from the stable period value 1 in the initial stage and the final stage.

  For ease of understanding, in FIG. 6A, the sign of the minimum reference current value Imin2 shown in FIG. 4B is changed to Imin, and the sign of the reference current value width ΔI2 is changed to ΔI.

  The correction coefficient K shown in FIG. 6B acts only on the minimum reference current value Imin in the reference current value map 122 of FIG. 6A, and does not act on the maximum reference current value Imax. That is, for the entire period (initial period, stable period, and end period) of the lifetime operation time TL, the maximum reference current value Imax uses the reference current value map 122 shown in FIG. 6A as it is, but the minimum reference current value Imin is The minimum reference current value Imin × K is used.

  Next, the operation of the second embodiment of the vehicle air conditioner 10 using the reference current value map 122 of FIG. 6A and the correction coefficient map 124 of FIG. 6B will be described with reference to the flowchart of FIG. In the flowchart of FIG. 7, the same step numbers are assigned to the same processes as those in the flowchart shown in FIG. 5, and detailed description thereof is omitted.

  In step S <b> 1, the lifetime operating time measuring unit 102 determines whether or not the fan switch 54 is turned on. If it is determined to be in the on state, the process proceeds to step S2.

  In step S <b> 2, the lifetime operating time measuring unit 102 reads the lifetime operating time TL of the blower motor 12 from the lifetime operating time storage unit 42 a of the EEPROM 42.

  In step S3, the lifetime operating time measuring unit 102 adds a new operating time to the read lifetime operating time TL, and in step S4, adds the new lifetime operating time TL to the lifetime operating time storage unit 42a. Save and update lifetime working time TL.

  Next, in step S7a, it is determined whether or not the updated lifetime operating time TL is a time within the lifetime t3 (TL ≦ t3).

  If it is determined that the lifetime operation time TL exceeds the lifetime t3, in step S11, the warning unit 30 is notified that the lifetime of the blower motor 12 has expired, and the process returns to step S1. In this case, the warning unit 30 displays on the display unit or the like that the blower motor 12 needs to be replaced and gives a warning to the user.

  In step S7a, when the updated lifetime operating time TL is within the lifetime t3, the correction coefficient map 124 shown in FIG. 6B is referred to, and the correction coefficient K corresponding to the updated lifetime operating time TL is read. The correction coefficient K is determined.

  In step S <b> 12, the applied voltage value detection unit 106 detects the applied voltage value Vm and supplies it to the reference current value correction unit 104 and the abnormality determination unit 110.

  Next, in step S13, the reference current value correcting unit 104 refers to the reference current value map 122 shown in FIG. 6A, and determines the maximum reference current value Imax and the minimum reference current value Imin from the applied voltage value Vm detected in step S12. And a corrected minimum reference voltage value K × Imin obtained by correcting the minimum reference current value Imin is calculated. The reference current value correction unit 104 supplies the calculated maximum reference current value Imax and the corrected minimum reference current value K × Imin to the abnormality determination unit 110.

  Next, in step S <b> 14, the energized current value Im is detected by the energized current value detecting unit 108 and supplied to the abnormality determining unit 110.

  In steps S15 and S16a, the abnormality determination unit 110 compares the detected energization current value Im with the calculated maximum and minimum reference current values Imax and K × Imin, and the energization current value Im is the maximum reference current value. If the value is below Imax (step S15: YES) and exceeds the minimum reference current value K × Imin (step S16a: YES) (Imax> Im> K × Imin), it is determined that the blower motor 12 is normal. Returning to step S1, when the value is not less than the maximum reference current value Imax (step S15: NO) or not more than the minimum reference current value K × Imin (step S16a: NO) (Im ≧ Imax or Im ≦ Imin), In step S11, the warning unit 30 is notified that an abnormality has occurred in the blower motor 12, and step S11 is performed. Back to. In this case, the warning unit 30 displays on the display unit or the like that an abnormality has occurred in the blower motor 12 (or that the blower motor 12 needs to be replaced instead) and gives a warning to the user. .

  As described above, in the second embodiment, the minimum reference current of the reference current value map 122 is determined by the reference current value correcting unit 104 according to the lifetime operating time TL of the blower motor 12 measured by the lifetime operating time measuring unit 102. After the value Imin is corrected, the energization current value Im is compared with the maximum / minimum reference current values Imax and K × Imin, so that the current of the blower motor 12 corresponds to the secular change of the energization current value Im of the blower motor 12. Abnormalities can be detected appropriately.

  Even in this case, the energization current value Im is non-uniform such as non-uniformity in contact with the commutator of the brush at the initial stage of the lifetime TL of the blower motor 12, wear of the brush and commutator at the end of the lifetime TL. Accordingly, in consideration of the fact that there is a large variation in the initial stage and the end stage compared to the stable period of the lifetime operating time TL, the reference current value width ΔI is set to the initial and lifetime operating time TL of the lifetime operating time TL of the blower motor 12. At the end of the period, since it is set wider than the stable period of the lifetime operating time TL, it is possible to appropriately detect the abnormality of the blower motor 12 in accordance with the secular change of the conduction current value Im of the blower motor 12. When the reference current value width ΔI is set to be wide, the maximum reference current value Imax is fixed, and the minimum reference current value Imin is set to the minimum reference current value K × Imin (initial and end K ≦ 1, stable period K = 1). By changing the correction, it is possible to perform correction in accordance with the actual situation that the current value Im becomes smaller than the current value Im in the stable period in the initial stage and the final stage.

  By performing the correction in this way, as in the first embodiment, it is possible to reduce the occurrence of misjudgment in the initial and final stages of the lifetime operating time TL, and it is possible to perform highly accurate abnormality determination in the stable period of the lifetime operating time TL. .

  Note that the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted based on the contents described in this specification.

It is a block diagram which shows the principal part structure of the air conditioning apparatus for vehicles which concerns on one Embodiment of this invention. It is a functional block diagram of the microcomputer shown in the example of FIG. It is a characteristic view which shows the relationship of the motor current of a blower motor with respect to lifetime operating time when an applied voltage value is a predetermined constant value. 4A is a reference current value map that is referenced at the beginning of the lifetime operation time, FIG. 4B is a reference current value map that is referenced during the lifetime of the lifetime operation time, and FIG. 4C is referenced at the end of the lifetime operation time. It is a reference current value map. It is a flowchart provided for operation | movement description of 1st Example. FIG. 6A is a reference current value map that is referred to in the stable period of lifetime operating time, and FIG. 6B is a map of correction coefficients for lifetime operating time. It is a flowchart provided for operation | movement description of 2nd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Air conditioning apparatus for vehicles 12 ... Blower motor 14 ... Microcomputer 16 ... Air-conditioning panel 40 ... Timer 42 ... EEPROM
42a ... Lifetime operation time storage unit 42b ... Reference current value storage unit 52 ... Air conditioning switch 54 ... Fan switch 102 ... Lifetime operation time measurement means 104 ... Reference current value correction means 106 ... Applied voltage value detection means 108 ... Energized current value detection means 110: Abnormality determination means 121-123 ... Reference current value map 124 ... Correction coefficient map

Claims (3)

A vehicle air conditioner comprising an abnormality determining means for detecting an applied voltage value and an energized current value of a blower motor and comparing the energized current value with a reference current value corresponding to the applied voltage value to determine an abnormality of the blower motor. In the device
A lifetime operating time measuring means for measuring the lifetime operating time of the blower motor;
Reference current value correction means for correcting the reference current value according to the measured lifetime operation time,
The vehicle air conditioner characterized in that the abnormality determination means determines an abnormality of the blower motor by comparing the reference current value corrected according to the lifetime operation time and the energization current value. The vehicle air conditioner according to claim 1,
The reference current value has a reference current value width between a maximum reference current value and a minimum reference current value. Widely set compared to the stable period of lifetime operating time,
The vehicle air conditioner characterized in that the abnormality determining means determines that the blower motor is abnormal when the energized current value is not less than the maximum reference current value or not more than the minimum reference current value. The vehicle air conditioner according to claim 2,
The vehicular air conditioner is characterized in that when the initial side and the end side of the reference current value width are set wide, the maximum reference current value is fixed and the minimum reference current value is lowered.

Images